I.
noun
ADJECTIVE
▪ belt , shoe
▪ brass , silver , etc.
VERB + BUCKLE
▪ do up , fasten
▪ undo , unfasten
II.
verb
Buckle is used with these nouns as the subject: ↑ knee , ↑ leg
Buckle is used with these nouns as the object: ↑ belt , ↑ seat belt , ↑ strap